A former assistant US attorney explained why most people seek to strike deals to keep themselves out of jail.

"If he flips, everyone he's associated with has exposure. And I'm confident that almost certainly, there is a 'there' there."

People close to President Donald Trump keep suggesting that his longtime lawyer Michael Cohen is likely to flip, or cooperate with the government by providing information on others in exchange for a lesser punishment.

One former assistant US attorney explained to Business Insider why it seems so likely.

Cohen and Trump have had a close relationship over the years. The lawyer has claimed intense loyalty to the president as a friend and adviser — once reportedly saying he would "take a bullet" for Trump — and handling sensitive matters for the president. That includes paying adult-film star Stormy Daniels $130,000 days before the election to keep quiet about an alleged affair.

But Cohen's loyalty is being tested ever since the FBI raided his office, home, and hotel room to obtain records and documents — including some that seem to be related to the Daniels payment. He's under investigation for possible bank fraud, and campaign finance violations, the Washington Post reported.

Cohen hasn't been charged with any crimes, but the prison sentence for such allegations — if proven — could be substantial, and it's rare that people face such a prospect without seeking a way out, said Mitchell Epner, a former assistant US attorney for the District of New Jersey.

RELATED: Members past and present of President Trump's inner circle

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Members past and present of President Trump's inner circle

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Members past and present of President Trump's inner circle

Hope Hicks: Former White House Director of Strategic Communications

Melania Trump: Wife to President Trump and first lady of the United States

Gary Cohn: Former Director of the U.S. National Economic Council

Michael Flynn: Former National Security Advisor, no longer with the Trump administration

Ivanka Trump: First daughter and presidential adviser

Gen. John Kelly: Former Secretary of Homeland Security, current White House chief of staff

Steve Bannon: Former White House chief strategist, no longer with the Trump administration

Jared Kushner: Son-in-law and senior adviser

Kellyanne Conway: Former Trump campaign manager, current counselor to the president

Reince Priebus: Former White House chief of staff, no longer with the Trump administration

Anthony Scaramucci: Former White House communications director, no longer with the Trump administration

Sarah Huckabee Sanders: White House press secretary

Donald Trump Jr.: First son to President Trump

Sean Spicer: Former White House press secretary, soon to be no longer with the Trump administration

"The question is when Michael Cohen started doing whatever he was doing, did he have the mental conversation with himself that 'I'm talking the talk, and if my time comes, I'm going to do my time, and then I'll go away and when it's time for me to come back, I'll come back,'" Epner, now an attorney at Rottenberg Lipman Rich, told Business Insider. "And if he made his peace with that before all of this started then it's really simple. He will stand up for whoever he's protecting and he will go away."

There are "very, very few stand up guys like that" when faced with possible prison time in excess of 20 years.

"When I was a prosecutor, there were some drug gangs that I dealt with that had stand up guys like that," he continued. "When we caught them, they might plead guilty and they might go to trial, but they were never going to roll on anybody. And you knew who they were, and you could tell from the very beginning when you were talking to their attorneys: 'don't come to us with a deal, it's not going to happen.'"

About 90% of the people Epner dealt with were looking for a deal, he said, adding that if the person hasn't had the conversation with themselves in advance about serving an extended jail sentence, it's even more likely they'll be looking to cut a deal.

"I don't know whether or not Michael Cohen is a tough guy," he said. "But when I hear things in the media like 'how is this going to affect my family, I need to take care of them' — if he is actually asking those questions, if that's real and not fake, then it seems extraordinarily likely that he flips. And if he flips, everyone he's associated with has exposure. And I'm confident that almost certainly, there is a 'there' there."

In recent days, those close to Trump have suggested that Cohen may very well flip if faced with serious charges.

Two sources close to Trump said the president's inner circle is actively discussing such a Cohen flip, Politico reported.

"When anybody is faced with spending a long time in jail, they start to re-evaluate their priorities, and cooperation can’t be ruled out," one Trump ally who knows Cohen told the publication.

The documents seized by the FBI in the Cohen raids could cause huge problems for Trump, the president and his allies fear per Politico.

"I think for two years or four years or five years, Michael Cohen would be a stand-up guy," a lawyer who is defending a senior Trump aide in special counsel Robert Mueller's probe told Politico. "I think he’d tell them 'go piss up a rope.' But depending on dollars involved, which can be a big driver, or if they look at him and say it’s not two to four years, it’s 18 to 22, then how loyal is he? Is he two years loyal? Is he 10 years loyal? Is he 15 years loyal?"

Jay Goldberg, an attorney who has represented Trump, told The Wall Street Journal that he spoke with Trump about Cohen and warned him to not trust his attorney if he's faced with criminal charges.

Cohen, Goldberg said, "isn't even a 1" on a scale of 1 to 100 where 100 would be taking "the bullet," so to speak.

"Without exception, a person facing a prison term cooperates," he said, adding however that he didn't "accept the notion of 'flip.'"

"'Flip' means to me that when faced with the potential of spending time in jail, he will tell the truth," he continued. "I don't think that was what the president was concerned about and that's not what I'm concerned about."

Goldberg suggested that Cohen would make up information on Trump to help get himself some "leniency."

The White House has sought to distance Trump from Cohen, meanwhile. White House press secretary Sarah Huckabee Sanders told reporters earlier this week that the two have "still got some ongoing things" but "the president has a large number of attorneys."

But Saturday morning, Trump sought to push back against the assertion that Cohen would flip if faced with charges, blasting a New York Times story on the subject.

Trump tweeted that the Times and reporter Maggie Haberman were "going out of their way to destroy Michael Cohen and his relationship with me in the hope that he will 'flip.'"

The president, who dined with Cohen at Mar-a-Lago in the weeks the preceded the raid and phoned him in the days that followed to "check in" on him, said his attorney is "a fine person with a wonderful family."

"Michael is a businessman for his own account/lawyer who I have always liked & respected," he continued. "Most people will flip if the Government lets them out of trouble, even if it means lying or making up stories. Sorry, I don’t see Michael doing that despite the horrible Witch Hunt and the dishonest media!"